Almost all passenger transport vehicles have exterior lights. They are provided for a wide variety of different purposes, such as for allowing the passengers and/or operators to view the outside, for passive visibility, for signalling purposes, etc. In the aircraft industry and other fields, exterior lights are highly regulated in terms of the light intensity distributions that are emitted from the lights.
For some exterior lights, it is desired and/or required by regulations to have a narrow opening angle of the emitted light. In other words, it is a design goal for some exterior lights to achieve a highly collimated output light beam. Previous approaches have not yielded good results of collimation at acceptable sizes of the optical structures needed for achieving the collimation.
Accordingly, it would be beneficial to provide a lighting structure for an exterior vehicle light unit that achieves an improved compromise between the degree of collimation and the space required for the lighting structure. Further, it would be beneficial to provide an exterior vehicle light unit making use of such improved lighting structure. It would also be beneficial to provide a passenger transport vehicle with such improved exterior vehicle light unit.